Pepper uses DIP, so RWFullscreenPepper should always use SetDeviceScaleFctor.

content/renderer/render_widget_fullscreen_pepper.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/render_widget_fullscreen_pepper.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 366 matching lines @@
 }
 
 WebWidget* RenderWidgetFullscreenPepper::CreateWebWidget() {
   return new PepperWidget(this);
 }
 
 GURL RenderWidgetFullscreenPepper::GetURLForGraphicsContext3D() {
   return active_url_;
 }
 
-void RenderWidgetFullscreenPepper::SetDeviceScaleFactor(
-    float device_scale_factor) {
-  RenderWidget::SetDeviceScaleFactor(device_scale_factor);
+void RenderWidgetFullscreenPepper::OnDeviceScaleFactorChanged() {
   if (compositor_)
-    compositor_->setDeviceScaleFactor(device_scale_factor);
+    compositor_->setDeviceScaleFactor(device_scale_factor_);
 }
 
 }  // namespace content